v0.3.10-pre.004

crates/ksp-raw-transaction-lib/src/signature.rs

@@ -1,5 +1,7 @@
 // file: crates/ksp-raw-transaction-lib/src/signature.rs
-// version: 1
+// version: 2
+
+use base64::Engine; // rust-rules: trait-import
 
 /// Maximum UTF-8 byte length admitted for one textual Base58 Solana transaction signature.
 pub const MAX_RAW_TRANSACTION_SIGNATURE_TEXT_BYTES: usize = 88;
@@ -50,6 +52,80 @@ pub fn parse_raw_transaction_signature(value: &str) -> ksp_core_lib::Result<ksp_
     return std::result::Result::Ok(ksp_store_api::RawTransactionSignature::new(decoded));
 }
 
+/// Extracts the first canonical 64-byte Solana signature from one complete Base64-encoded transaction wire.
+///
+/// The compact signature-count prefix must use its canonical short-vector representation, contain at least one signature,
+/// and the decoded transaction must retain message bytes after the declared signature array.
+pub fn extract_raw_transaction_signature_from_binary_base64(value: &str) -> ksp_core_lib::Result<ksp_store_api::RawTransactionSignature> {
+    if value.is_empty() || value.len() > ksp_store_api::MAX_RAW_PAYLOAD_BYTES {
+        return std::result::Result::Err(crate::signature_error());
+    }
+    let decoded = base64::engine::general_purpose::STANDARD.decode(value);
+    let decoded = match decoded {
+        std::result::Result::Ok(decoded) => decoded,
+        std::result::Result::Err(_) => return std::result::Result::Err(crate::signature_error()),
+    };
+    if base64::engine::general_purpose::STANDARD.encode(decoded.as_slice()) != value {
+        return std::result::Result::Err(crate::signature_error());
+    }
+    let prefix = decode_signature_count(decoded.as_slice());
+    let (signature_count, prefix_len) = match prefix {
+        std::result::Result::Ok(prefix) => prefix,
+        std::result::Result::Err(error) => return std::result::Result::Err(error),
+    };
+    if signature_count == 0 {
+        return std::result::Result::Err(crate::signature_error());
+    }
+    let signatures_len = match signature_count.checked_mul(64) {
+        std::option::Option::Some(length) => length,
+        std::option::Option::None => return std::result::Result::Err(crate::signature_error()),
+    };
+    let message_offset = match prefix_len.checked_add(signatures_len) {
+        std::option::Option::Some(offset) => offset,
+        std::option::Option::None => return std::result::Result::Err(crate::signature_error()),
+    };
+    if message_offset >= decoded.len() {
+        return std::result::Result::Err(crate::signature_error());
+    }
+    let first_end = match prefix_len.checked_add(64) {
+        std::option::Option::Some(end) => end,
+        std::option::Option::None => return std::result::Result::Err(crate::signature_error()),
+    };
+    let first = match decoded.get(prefix_len..first_end) {
+        std::option::Option::Some(first) => first,
+        std::option::Option::None => return std::result::Result::Err(crate::signature_error()),
+    };
+    let mut signature = [0_u8; 64];
+    signature.copy_from_slice(first);
+    return std::result::Result::Ok(ksp_store_api::RawTransactionSignature::new(signature));
+}
+
+fn decode_signature_count(bytes: &[u8]) -> ksp_core_lib::Result<(usize, usize)> {
+    let mut value = 0_usize;
+    for index in 0..3_usize {
+        let byte = match bytes.get(index) {
+            std::option::Option::Some(byte) => *byte,
+            std::option::Option::None => return std::result::Result::Err(crate::signature_error()),
+        };
+        let payload = usize::from(byte & 0x7f);
+        let shift = index * 7;
+        value |= payload << shift;
+        if byte & 0x80 == 0 {
+            if index != 0 {
+                let minimum = 1_usize << shift;
+                if value < minimum {
+                    return std::result::Result::Err(crate::signature_error());
+                }
+            }
+            if value > usize::from(u16::MAX) {
+                return std::result::Result::Err(crate::signature_error());
+            }
+            return std::result::Result::Ok((value, index + 1));
+        }
+    }
+    return std::result::Result::Err(crate::signature_error());
+}
+
 fn base58_digit(byte: u8) -> std::option::Option<u8> {
     return match byte {
         b'1'..=b'9' => std::option::Option::Some(byte - b'1'),